Hubmotor spokes loosening

[davevelo]

Warning! If you have a powerful hubmotor and have regen enabled, be sure to occasionally check your spoke tension. Mine became loose to the extent that almost all of them were completely slacked.

 

[wesnewell]

Once you get them to the proper tension they should not come loose again. I've got 12K + miles on mine with none coming loose. One di break at ~10K miles though.

 

[amberwolf]

It's not the regen, it's just an incomplete wheel build--not tensioned properly to start with.

I recommend reading the Sheldon Brown website's wheelbuilding page(s), as well as the various wheel / spoke threads here on ES. These should give you enough information to permanently fix your wheel.

 

[dogman dan]

Even a weak hub motor will need the spokes tightened some after the first 50-100 miles. Or longer, if the wheel build is very good.

Usually I can hear mine when they start to get a tad loose. But don't go thinking just keep cranking them too tight, then you break spokes, or rip em out of the rim.

You just have to keep up on the spokes from time to time, just like lubing a chain, or adjusting brakes. The harder you ride, the more often you need it. Hell, back in the day, pedaling a 10 speed in 1976, I rode so hard I had to true my wheels weekly.

 

[davevelo]

Warning! If you have a powerful hubmotor and have regen enabled, be sure to occasionally check your spoke tension. Mine became loose to the extent that almost all of them were completely slacked.

Thanks for all your replies. I am an experienced wheel builder but first time using a hubmotor. I forgot to mention that, because of the large size of the motor mounted onto a 20" rim, it was necessary to radially spoke the wheel. I believe the back and forth twisting motion due to acceleration and regeneration caused the spokes to lose tension.

 

[amberwolf]

I run radial lacings on my 3 hubmotored 20" wheels, one on the rear of CB2 and two on the rear of SBC, and none of them have issues with loosening up...but they also all have normal-gauge spokes (Sapim 13/14 butted on the SBC, and Sapim 13 on CB2), whcih allows good tensioning without rim damage.

On SBC there is not only regen, but active braking that is even harder on the wheels, as well as tremendous sideloading in turns (which the CB2 wheel doesn't see since it's a bike, not a trike).

I've also tried the 12g whatevers that came on ebikekit and crystalyte OEM wheels and rims, and those *did* have problems loosening up, and tensioning them enough to stop that caused rim failure over a pretty short time. (this alos happened on larger 26" wheels with 2x lacings, as well as the 20" radials).

I don't know for sure that the spoke *gauge* vs bicycle rims is the issue, but it is pretty high on my suspect list.

 

[Ykick]

Did you build this wheel?

 

[ColinB]

I've got the 20" rim and HS3548 Crystalyte motor from Grin (eBikes.ca) and have had to tension spokes multiple times. I was not running regen (the first year) and I still had issues with some of the spokes loosening.

I'm not sure what gauge spokes they are - I used what it came with. I'm on my second rim now. (Wore out the braking surface.) You just check the spokes on a regular basis, and if you hear any extra little noises. Since the spokes are so thick and so short, I find it really hard to gauge the tension. I just guess - tension them up until the creaky noises stop when I ride, and try to get them all as even as possible.

I put locktite (blue?) on the spoke threads. I think it isn't proper... but it is what I wanted.

Colin

 

[davevelo]

I run radial lacings on my 3 hubmotored 20" wheels, one on the rear of CB2 and two on the rear of SBC, and none of them have issues with loosening up...but they also all have normal-gauge spokes (Sapim 13/14 butted on the SBC, and Sapim 13 on CB2), whcih allows good tensioning without rim damage.

On SBC there is not only regen, but active braking that is even harder on the wheels, as well as tremendous sideloading in turns (which the CB2 wheel doesn't see since it's a bike, not a trike).

I've also tried the 12g whatevers that came on ebikekit and crystalyte OEM wheels and rims, and those *did* have problems loosening up, and tensioning them enough to stop that caused rim failure over a pretty short time. (this alos happened on larger 26" wheels with 2x lacings, as well as the 20" radials).

I don't know for sure that the spoke *gauge* vs bicycle rims is the issue, but it is pretty high on my suspect list.

Hmm, I'm using 12 gauge with my HS3540. The Exal rims came from Crystalyte. I must say the rims were not to be liking. Although they appear strong, their quality did not meet my expectations.

 

[davevelo]

I've got the 20" rim and HS3548 Crystalyte motor from Grin (eBikes.ca) and have had to tension spokes multiple times. I was not running regen (the first year) and I still had issues with some of the spokes loosening.

I'm not sure what gauge spokes they are - I used what it came with. I'm on my second rim now. (Wore out the braking surface.) You just check the spokes on a regular basis, and if you hear any extra little noises. Since the spokes are so thick and so short, I find it really hard to gauge the tension. I just guess - tension them up until the creaky noises stop when I ride, and try to get them all as even as possible.

I put locktite (blue?) on the spoke threads. I think it isn't proper... but it is what I wanted.

Colin

I used anti-seize but with this wheel, am not sure that was a good idea. After retightening the spokes and truing the wheel, I went around and dropped superglue into all the nipples. I hope that helps.

 

[amberwolf]

I've got the 20" rim and HS3548 Crystalyte motor from Grin (eBikes.ca) and have had to tension spokes multiple times. I was not running regen (the first year) and I still had issues with some of the spokes loosening.

Unfortunately, AFAIK those come with the 12g (at least) spokes on a cheap rim; that's what mine came wiht (HSR3548). Similar problems on mine, unable to fully tension those spokes, only resolved by changing rims/spokes. (might've been able to fix it with the same size/type of spokes, but with the stronger rim, but havent' tried that experiment).

See my CrazyBike2 thread around the first/middle part of the last half of 2013 for details about that wheel and the problmes I had, which were mostly resolved by using the Sapim 13g spokes instead, thoug there was an experimental lacing method tried first, half-radial, half 1x, which didnt' work out fully partly because of the bends in the 1x spokes, but mostly becuase the rim itself was not very good to start with and was then damaged by a pothole impact.

What fixed the problems permanently was changing to a much better rim (ex-Zero wide rim), and full radial lace with those Sapim 13g spokes.

I used the Sapim 13/14 butted spokes and the same kind of rim to lace up the X5304 full radial, and have not had issues with that, either, despite the sideloading, accel, and regen, and the weight loads.


Anyway, again, I don't *know* that it's the spoke size vs rim type, but it appears it sure could be.

 

[Chalo]

Warning! If you have a powerful hubmotor and have regen enabled, be sure to occasionally check your spoke tension. Mine became loose to the extent that almost all of them were completely slacked.

That has more to do with the fact that they're way too thick than with the magnitude of any applied loads. For whatever reason, e-bike manufacturers and buyers are stuck on the idea that thick spokes are better. They're not, unless you match them with thick rims that can take proportionally higher tension.

Bicycle rims, bicycle spokes. That's 14ga or thinner.

 

[dogman dan]

Yep. which is why you have to keep a close eye on wheels that did use the 12g spokes.

I'm sure though, that regen does make the problem worse.

A definite no brainer to re lace the wheel, if you have access to a spoke threader.

 

[Chalo]

Everyone can get the benefits of Danscomp.com's spoke machine to get 14ga spokes cut to measure for a quarter apiece. You can't beat it.

They even sell 14-17ga Sapim spokes cheaper than my shop sells straight gauge DT spokes. I don't recommend those for hub motor builds, but they're just right for the loose side of dished wheels.

 

[dogman dan]

25 cents a spoke is a good deal. Higher priced custom spokes has me running a lot of wheels with 12 g. Thanks for the heads up on the source.

http://www.danscomp.com/products-PARTS/435905/Sapim_Stainless_14G_Spoke.html

 

[davevelo]

Warning! If you have a powerful hubmotor and have regen enabled, be sure to occasionally check your spoke tension. Mine became loose to the extent that almost all of them were completely slacked.

Thanks for all your replies. I am an experienced wheel builder but first time using a hubmotor. I forgot to mention that, because of the large size of the motor mounted onto a 20" rim, it was necessary to radially spoke the wheel. I believe the back and forth twisting motion due to acceleration and regeneration caused the spokes to lose tension.

Update: After retightening the spokes and dropping superglue down the nipples, they seem to be retaining their tension. When building a new wheel such as this, suggest checking the spokes after a few rides. Could have been just the wheel settling in that loosened them.

 

[Ykick]

25 cents a spoke is a good deal. Higher priced custom spokes has me running a lot of wheels with 12 g. Thanks for the heads up on the source.

http://www.danscomp.com/products-PARTS/435905/Sapim_Stainless_14G_Spoke.html

Even their 13/14ga butted Sapim spokes only cost 50 cents for those folks not into messing with washers. 13/14 butted isn't on their website but ask if/when you call with sizes.

Oh btw, Danscomp shipping is always very reasonable - around $5-6 for my orders of 36-72 spokes.

 

[Mundo]

For the do it yourself people, what spoke threader(sp) is recommended?

Some bike shops, want nothing to do with hub motors.

 

[Drunkskunk]

For the do it yourself people, what spoke threader(sp) is recommended?

Some bike shops, want nothing to do with hub motors.

None. A good spoke threader, like the Phill Wood spoke machine, costs around $3k used on ebay. (example)
A lower quality and therefor cheaper one isn't worth the time or effort when you can order pre-cut spokes and get them in a day or three for the same cost as uncut spokes.

 

[davevelo]

For the do it yourself people, what spoke threader(sp) is recommended?

Some bike shops, want nothing to do with hub motors.

None. A good spoke threader, like the Phill Wood spoke machine, costs around $3k used on ebay. (example)
A lower quality and therefor cheaper one isn't worth the time or effort when you can order pre-cut spokes and get them in a day or three for the same cost as uncut spokes.

If you're not going into business but just want to DIY, pick up the proper size die from a tool shop. Sorry, don't know the exact sizes. Try http://www.sheldonbrown.com/